Deduced on Sight
by BonesDon'tMelt
Summary: Sherlock and John have been corresponding through letters, and are finally going to meet when John returns from his tour in Afghanistan. Except there's one problem: Sherlock doesn't know John's back, and John wasn't expecting to run into his pen pal.
1. The meeting- John

AN: Got this idea while reading "Letters to a Soldier" by Pakmai. Really great story, I recommend it.

* * *

John Watson was not exactly having a good day.

In fact, he hadn't been having a good _month_.

It started off well enough. He'd gotten a letter from his correspondent from London, which was always interesting. He was a strange and rather blunt bloke named Sherlock Holmes, who had only written a letter to an anonymous soldier (who had just so happened to be Captain John Watson, MD) because he was forced to by a drug detox clinic (or prison, as he preferred to call it) as part of their twelve steps or whatever. Sherlock was quite adamant that admitting he had a problem to some random soldier on the other side of the world would in no way help, but figured he would do it if it would get his captors off his back.

But back to the point. Sherlock had written about a rather interesting case he had just helped Detective Lestrade with, involving one victim with three separate murderers (or, rather, three different people who were _trying_ to kill him and each thought they _had_ ). It was fascinating, as Watson always thought, but before he could draft a reply he had been called out to assist the wounded in the field.

Where he had promptly gotten shot.

He'd been unconscious for days, having lost quite a lot of blood before they could get him back to base, and after that had been confined to a bed for a week while they made plans to have him shipped back to London.

After _that_ , he hadn't even been able to write Sherlock for a few days more because of an irritating combination of lack of materials and his own injury. When he finally did get off a letter he had been practically released, and a few of the other patients had been adamant that letters, real physical _letters_ on paper written with real ink and everything, were old fashioned things saved for being romantic. Perhaps Sherlock had a point with his whole "everyone in the world is an idiot" mentality.

And on top of all that were the therapists. Those bloody _therapists_. He was beginning to empathize more and more with Sherlock's detox experience, which was a _whole_ other kettle of fish. Really, he felt like he should be worried that he was beginning to share world views with a self-proclaimed sociopath, ex-drug-addict who, as far as Watson could tell, was in trouble with the police as much as he helped them. Sherlock had written that therapists were "fools. Absolute imbeciles whose miniscule brains couldn't comprehend how to make _breakfast,_ much less what was going on in a mind such as" his. At the time Watson had first read it (this had been his first letter, which was intriguing enough that Watson had written back), he thought Sherlock was being arrogant and perhaps just lashing out because he was confined. Later, he realized that Sherlock actually was a genius and people really _didn't_ have any idea what was going on in his head. _Now_ Watson was inclined to think the description was entirely accurate even for himself, who had average intelligence.

Which was bad. The poor girl was just doing her job, after all, but Watson really couldn't help but hate her for it, just a bit.

He had just gotten out of another session with her, which was why this particular day was bad. They seemed to be making progress- that's what Mrs. Thompson had said, anyway. He had actually said words to her besides "good morning" and "bye" today, so he figured that might be what she meant. On the other hand, she seemed absolutely determined to make something of his letter exchanges with Sherlock (a man he had never even heard the voice of, much less _met_ ). Even if it wasn't a romantic attraction (which she had been oh-so-subtly hinting at, the wretched old hag- no no, wonderful woman who was trying to help him. Yes), she theorized it was a sort of mutual support by which the crippled ex-soldier and rejected ex-addict could continue living and overcome both of their mental illnesses.

John thought that was a load of poppycock, and had said as much. Those were the words he had uttered that made Ella Thompson declare that they were making "progress".

John was now wandering the streets of London with no purpose and no destination. He didn't _like_ not having something to head towards, but told himself that the undefined floating would do him good. That's what that bloody therapist had said in their first session ("living a life with a single-minded purpose for so long can cause a sense of uselessness when soldiers return to civilian life, but..." and then John couldn't remember the exact words, but it was basically that a little bit of uselessness made people more flexible and it was good for the body or some rubbish like that), but John absolutely _abhorred_ not doing anything. He was a soldier, a doctor, both professions where sitting back and doing nothing was hardly an option. And even the waiting had a purpose- waiting for the right moment to strike, waiting for medicine to take affect, waiting for the patient to either die or recover. Never just sitting, doing nothing. Like he was. Right now. On this uncomfortable bench. Right now.

Jeez, this whole civilian thing was rough.

John struggled to his feet and hobbled in a random direction, deeper into London. This was really a no-win situation; walking reminded him of his issues and injuries, not to mention it being quite the workout, but sitting still just gave him time to _think_ and _reflect._ He just needed something to _do._

Despite these thoughts, John sighed. Finding something to do was a slim to nothing chance for a crippled army doctor who could no longer do surgery _or_ fight.

Spotting a crowd up ahead, the doctor decided he might as well see what was going on. He wasn't really one to shove his way to the front and demand answers, he preferred fading into the background and observing, only asking when he had absolutely no idea. That was why he didn't insert himself into the crowd, but hovered around the edges; close enough that a casual passerby would think he was part of the throng, but separated enough that he was able to observe without being jostled and pulled in by the people.

It seemed to be a crime scene. A murder, based on the grim faces around him, and either it was very grisly and word had gotten out or it was part of a serial case because the crowd was already whispering about how horrible a way to die it would be. Though none of them had bothered to say what was so terrible, so John decided not to dwell on it. He had seen too many grisly deaths; he knew better than to let his mind supply a scenario, though it would be all too eager.

After about ten minutes (in which John had discovered that there were two victims in the house, they were mutilated beyond recognition, some guy everyone referred to as "the freak" had been the only one to make any significant discoveries, and when doctors told you to rest you should probably listen because his shoulder was killing him) John decided he'd better be off. Probably to a park bench, to sulk some more, because he really didn't want to return to that bloody "recovery center". More like a prison.

Hmm. That reminded him, he could hunt down Sherlock if he got _that_ bored. He did have the nut job's address, after all, for sending letters. He had fallen out of touch with every friend he had that wasn't in the military save for that particular genius, if Sherlock could really be called his friend. He hadn't sought out the man yet only because John was having a bit of a hard time talking to people, but he was adjusting. Maybe speaking to someone who wasn't military or ex-military (besides the bloody therapist) might do him some good.

Mind made up, John began hobbling off. After a moment he realized he had no idea where he was going and turned back.

"Excuse me, but do you know where Baker Street is?" He asked a random crowd-goer. The man did know and gave him directions. John nodded and went to head off (in the _right_ direction this time), but didn't get more than two steps.

Because the window on the second floor in the center of the crime-scene house (the room John had figured out was where the murders had taken place thanks to the blood splatter on the glass) was flung open.

"Watson! You've been shot!"

John didn't know what made him say it. He had never heard this voice before, nor seen the tall, pale man with cheekbones that could probably cut glass. He was usually very polite to people he had never met before. He should have said something like "who are you" or "how do you know who I am". But instead, John turned to look squarely at the man in the window (who was being yelled at by a woman to "close the window, freak") and it just slipped out.

"How observant of you, Sherlock."

* * *

AN: Common sort of plot, but I hope my little twist made it a worthwhile read. I've got another chapter coming in the next few days of Sherlock's perspective.


	2. The meeting- Sherlock

AN: Woot! Two in as many days! Enjoy, dear readers.

* * *

Sherlock had been having a not-boring day.

In fact, he'd been having a not-boring _month_.

Not-boring was really the closest Sherlock ever got to admitting something made him happy, so in reality the last month had been _fantastic_.

Four of his experiments had been successful and informative, one had failed in a rather informative way, and a sixth blew up. Like, C4 level explosion. Which may have been because he was attempting to make C4 and it hadn't been as stable as he'd thought. He'd gotten yelled at by both Lestrade _and_ Miss Hudson for that one, but at least the day had been exciting and he'd been let off with a warning by both the police and the landlady.

He'd also had three interesting cases. _Three!_ Well, one interesting case, one that ended up being only moderately exciting, and the one he had been presented with this morning that was shaping up to be interesting.

All in all, his next letter to John would be a long one.

He'd never known that having someone actually interested in what he had to say simply because he knew instead of to some means to an end (putting up with him for a case, for instance) was so liberating. Now, Sherlock did not need other's approval to be vindicated; if he did he would have fallen apart long ago. But John's sincere compliments and honest surprise that wasn't tinted with the usual bitterness was refreshing.

Plus the fact that John didn't seem to be entirely hopeless at the science of deduction helped too. He wasn't smart compared to Sherlock of course, only Mycroft held that title (not that Sherlock would ever admit that out loud, Mycroft would probably have it recorded somehow and play it back to him whenever Sherlock was being difficult), but he seemed leagues above the mindless masses that Sherlock tried so hard to avoid. He was certainly a species above Anderson, who almost definitely had the brain of a monkey, and was messing up the crime scene even now.

Actually Sherlock didn't technically know that, he was on his way over to the crime scene now and hadn't yet arrived, but based on past experiences it was a safe bet.

When Sherlock arrived at the crime scene (ignoring the growing crowd of idiots who had nothing better to do) his eyes lit up like fireworks.

Oh, it was _Christmas!_

Two dead bodies mutilated beyond recognition. The police couldn't even tell gender (idiots. They were obviously both female), _and_ it was a locked-room murder!

Of course, Sherlock didn't say this, and he repressed the manic grin attempting to spread across his face. John had brought it to his attention (about two letters ago) that grinning and expressing excitement at a crime scene was "a bit not good". Not that he really cared what others thought of him and it's not like John would know, but the doctor had made a rather convincing argument about why not being thought of as a psychopath would be helpful.

After his first step into the room where the murders had actually taken place, even self-proclaimed sociopath Sherlock Holmes needed a moment to come to terms with the carnage within. Blood smeared the walls, was pooled on the floor, the two yet-unidentified victims lay in the center of the room. Unlike most people, who gasped, eyes wide and searching around the room, Sherlock then merely raised an eyebrow and shoved any emotion conjured by the scene into a locked room of his mind palace, beginning to pace around the room and taking everything of significance.

"As always, Anderson has missed the most obvious of clues," Sherlock scoffed, examining the blood around the bodies rather than the bodies themselves. There were a few beats of silence in which Donovan scoffed and muttered and Lestrade waited for him to continue. Anderson had left the room when Sherlock entered the house, because the Consulting Detective refused to deduce while he was near.

"What did we miss, Sherlock?" Lestrade asked, seeing that their eccentric helper wasn't going to continue on his own. Sherlock had begun to examine the walls and floor for any sign of a secret door- if the killer had used the one window that would be so _dull_.

"Obviously," Sherlock started with a frown. The frown was less because of police incompetence and more because it was beginning to look like the killer _had_ used the window. He wandered over and looked out, a glint catching his eye. He stopped his condescending sentence mid-ridicule.

The glint was from a necklace. A necklace on a man who was on the shorter side of average height, with blond hair in a cut that may have been army just a few weeks ago (it was slightly shaggy, just discharged then). He was leaning on a cane with one arm and the other was held to him in a sling though the arm itself seemed uninjured.

Dogtags, most likely, military, afghanistan. Recent discharge, medical reasons. Probably shot in the shoulder. Not just a soldier though, a doctor. Army doctor.

It wasn't the dogtags, though, that had Sherlock deducing this person. It was what he was doing; _how_ he was doing it. He was with the crowd outside, but had separated himself from the rest in a way most wouldn't pick up on. Trust issues, probably. He wasn't looking at the house like the others either; he was listening, to everything, to everyone. His gaze did shift to the house, but not in the excited or worried frenzy of the others; in a calm and methodical manner, the air of a man who was simply trying to solve a puzzle for lack of anything better to do.

"Obviously _what_ Sherlock?" Lestrade asked, getting a bit impatient. Sherlock ignored him, much too focused on the enigma outside to bother with this trifle. Something seemed familiar about this man; not in the way that they'd met before, but in the way Sherlock thought he should be able to figure out who this was, or at least who the army doctor reminded him of.

Oh. Army doctor.

John.

Sherlock scrutinized the man though the one window, ignoring the blood that slightly obstructed his view. An army doctor who had been in Afghanistan until just a few weeks ago, his hair was the correct shade (a strand had been accidentally attached to John's sixth letter), and he'd thought that John's letter was taking a bit longer than usual. A delay, then, such as, say, getting shot.

The general story fit, then. But still, it wasn't enough conclusively.

The man began to hobble away and Sherlock made a mental note to check on whether or not he'd gotten a letter when he got home (he may have forgotten to look the past week) but turned back before Sherlock had turned away. Sherlock was a proficient lip-reader, and the army man had definitely just asked where Baker Street was. That, with all other considerations, meant that there was an overwhelming possibility of this being John.

John began walking away once more, but Sherlock couldn't have that. His limp was psychosomatic and his hand tremor would definitely be irritating him; Sherlock was almost willing to bet that his therapist had gotten the reasons for both completely wrong. He could run out of the crime scene and fetch John himself (he could bring John up here and show these Yarder idiots what a real doctor would make of this), but that seemed much too boring. So instead he flung the window open (completely ignoring Donovan's ranting about his obvious psychotic tendencies) and got John's attention. He decided to use Watson, though, because it was a much less common name.

"Watson! You've been shot!"

He expected at least a moment of shock. Perhaps a bit of fear as the doctor tried to figure out who had just called out to him. At the very least, a question about how they knew each other. But no, John simply turned, looked him straight in the eyes, and replied calmly.

"How observant of you, Sherlock."

Calm, collected, and smarter than Sherlock gave him credit for. Oh yes, John was _definitely_ going to have to stick around.

* * *

AN: I've got another chapter or two planned- you get to find out what Sherlock found so interesting about the blood _and_ John meets the Yarders!


	3. The Case

AN: Here's a thanks to everyone who has reviewed, followed, or even just read this story! I hope you like this last chapter!

Disclaimer: I do not own Sherlock, nor a _m_ I Sherlock, which is probably why my deductions leave something to be desired!

* * *

The manic grin that Sherlock had been repressing since he had heard this latest case was locked-door split his face. John, still down in the crowd (many of whom were now looking at him and whispering to each other) felt he should probably be more worried than he was about that grin. Honestly, the grin looked at home on the Consulting Detective's face.

"What are you waiting for? Come up here, John!" Sherlock ordered as if John should have been up in the crime scene with him the moment he arrived.

"But-" His objection went unheard as Sherlock snapped the window closed and disappeared from sight.

The crowd parted before him as if he were some kind of royalty.

Or a leper.

Probably the latter, based on how they saw Sherlock. He was "the freak's" friend after all.

John made his way up to the police tape and hesitated. _Technically_ he could go in. He could pull rank as a doctor and soldier, and he _had_ gotten permission from someone working the case. But the man apparently manning the tape was giving him a rather nasty glare.

"Only police allowed," the man sneered at him. John wondered if he was just naturally angry at people trying to break into crime scenes or if it was because he was associated with Sherlock. The genius was, after all, not exactly great with people. He had admitted that in his first letter and, while John personally thought his deductions were brilliant, he could see how they would alienate him from others.

"Sod off, Anderson," Sherlock snapped as he strode out of the house, "he's with me." Sherlock then lifted the police tape and stared at John until he had ducked under.

Ah, Anderson. John's smile, which he had maintained throughout the ordeal, became a mite less genuine. He had heard about Anderson from Sherlock. While he was certain the man was smarter and more competent than Sherlock made him out to be, John was also fairly certain that his spiteful behavior towards Sherlock had not been exaggerated and John, being a very loyal man who counted Sherlock as a friend, didn't appreciate that.

Seeing that Anderson was about to retort and Sherlock's friend had gotten slightly less friendly just with the mention of his name, Lestrade, who had followed Sherlock from the crime scene, decided not to risk a police assault.

"Mr. Watson, was it?" He asked carefully.

"Doctor, actually," John shrugged.

"Doctor?" Lestrade asked, eyebrow raised. It was obvious that everyone here was confused at the cheerful greeting he had received from Sherlock but, being too polite to ask right out, Lestrade had asked a different question.

"Captain John Watson, MD, recently returned from military service in Afghanistan with an honorable discharge on medical grounds after being shot in the shoulder. The limp is psychosomatic, yes?" Sherlock rattled off, finally getting the mild shock he had expected from the doctor before. John had never actually seen him on a roll before, merely hearing about his skills through their letters.

"Brilliant. Absolutely brilliant," he said after his moment of shock wore off, an easy smile lighting up his features. Sherlock positively preened at the praise. "Anyway, I'm assuming you're Detective Lestrade? Sherlock's mentioned you," John continued, turning to the detective and adding that last bit when Lestrade looked mildly alarmed.

"Assuming, John?" Sherlock scoffed, tone disparaging.

"Fine. I've _deduced_ that you are Detective Lestrade."

"Yes yes, enough chat," Sherlock cut off any further conversation. He was getting _bored_ with all this talking; there was a crime scene just one staircase away! "Come John, a crime scene! Two mutilated women in a locked room!" He swept back inside without another word, John following with an apologetic smile at Lestrade.

As they approached the room, Sally Donovan saw them coming. She had been listening to their conversation from the crime scene, and knew that Sherlock was planning on bringing John to the gruesome room. Always assuming the worst of Sherlock, and taking into account the fact that even Detective Lestrade (the most senior of them and usually able to ignore the gore of the job rather well) had balked at the carnage, Sally immediately thought that this was some twisted experiment of Sherlock's- subjecting this poor normal-looking man to the terror in that room.

Which, you know, it _may_ have been a little bit, but mostly Sherlock was curious as to what John could make of the room itself rather than his initial reaction. He was willing to bet that the doctor would be able to make more headway in this case in the first minute than any of the Yarders had in hours.

"You don't want to go in there," Donovan said, stepping in front of John to stop him from walking into the room after Sherlock. Already he could smell the stench of blood, and see some seeping from under the door. "I don't know how you know the freak, but you should get away from him while you still can. Sherlock Holmes doesn't have _friends_ , he's using you for something."

John regarded her with an unreadable expression for a few moments before giving her a razor-edged smile.

"Sally Donovan, I take it. Sherlock may not have friends, but I do, and I count him as one of them, so I would greatly appreciate if you would stop attacking the people helping society and begin searching for those who commit crimes such as the one in there," he said faux-pleasantly, gesturing to the room she was still blocking from his path. The whole statement was said in a deceptively mild voice; an average-sounding one. Not low, not high, not fast or slow. Unbelievably average, just like the man it belonged to. But, at the same time, it had an underlying current of authority; a promise that if Donovan continued to block his way or insult those he considered friends, _something_ , something unspecified and somehow terrifying, would happen.

She stepped aside.

The other Yarders looked on in disbelief. Sally Donovan was courageous to the point of stupidity in that she never backed down from a verbal fight, even from Sherlock Holmes who had never _lost_ one such fight (except to his brother, not that anyone else had to know about those times), and yet she had stepped aside for this man.

"Thank you," John said pleasantly, gracing her with one of those easy smiles as he walked past.

The room was worse than John had imagined, but his reaction was the second thing in only twenty seconds that clued Lestrade into the fact that John wasn't merely some army doctor. Several of his people had had to run out of the room to puke when they first saw the mess, and many still examining the crime scene still looked nauseous and uneasy.

John's nose scrunched as the full smell hit him, face showing shock, but he quickly recovered at looked around. At the blood coating nearly every surface a twinge of disgust was shown in his eyes; at the substance itself, but mostly at the monster who had done this. When his eyes settled upon the bodies, the prevailing emotion was not disgust or horror, as it had been with nearly every other person Lestrade had seen, but sadness; a deep, penetrating sadness that said John had seen things this bad and _worse_ , and he could do nothing to reverse it, but if he could have stopped it he would have.

Even that didn't last long. It was quickly replaced by confusion, and Lestrade and the others mirrored the emotion as they watched John glance between the bodies and the blood.

"You've seen it, haven't you John?" Sherlock asked with a victorious gleam in his eye. He'd _known_ John would have a brain; it was just so perfect that he could show the Yarders that he wasn't the only one in the world who wasn't an idiot like them.

"Are these the only bodies?" John asked, not answering Sherlock's question directly, but the Consulting Detective already knew the answer. He moved forward, examining the bodies a bit more closely.

"Yes... Why?" Lestrade asked, wondering vaguely if he should order everyone to continue with their jobs. Every Yarder was watching Sherlock and John, having stopped working completely, and Lestrade decided to allow it because it wasn't like they were getting anywhere anyway.

Sherlock sent John a look that boiled down to _I told you they were idiots_ and John gave him one back that said _Sherlock, be nice and clue them in while I examine the bodies._

"Obviously," Sherlock began in a most put-upon tone of voice, sounding as if he were talking to a college student who didn't know the alphabet, "the amount of blood outside of the bodies alone is equal to at least seventeen pints of blood. The average adult has roughly ten pints, so the blood could have been from them except they haven't been bled. This blood is someone else's; one to three more victims depending on the amount of blood the other two have lost and how much blood was taken from each." He looked to John again as if asking a question, though he didn't verbalize anything.

"Looks like around ten of the pints aren't theirs. They didn't bleed to death, they've lost about three pints each. The mutilation was post-mortem so they actually didn't bleed that much; they were poisoned."

"Poisoned?" Echoed several of the onlooking Yarders. Lestrade was not one of them; he was torn between irritation at Sherlock's smug satisfaction and almost effortless way of making his men look like fools and admiration for his deductive skill and John's expertise.

"Yes, as anyone who is not a complete and _total_ idiot can see." John was unsure if he should be insulted that he was simply not a _total_ idiot instead of smart, or flattered that Sherlock had ranked his mental faculties higher than every Yarder in the room. "The mutilation is extensive, yet the actual _bloodpool_ is small and the bodies have obviously not been bled, therefore the injuries happened post-mortem to cover up the real means of murder. Smelling the mouth gives away the poison, and the rest is obvious!" Sherlock ended his explanation, already bored of spelling out each step of this simple case. "The landlady is a chemist, arrest her and her husband if he is a rock-climber and butcher."

Then Sherlock began walking out the door, not even waiting for John as the shorter man scrambled to keep up.

"Sherlock, what about the other victims?" Lestrade called after the infuriating man.

"Pig's blood!"

John looked at Sherlock in surprise. He was able to follow most of the man's deductions well enough, but he had no idea where that one had come from.

"How did you know it was pig's blood?"

"The blood was obviously spread purposely, therefore it was a distraction, not a boast of other unfound victims. There was also a distinct smell one would find in a butcher shop, and some of the blood was colder than room temperature, which means it had been stored in a refrigerator. That, along with the fact that the building the murder took place in is owned by a couple whose name is on the butcher shop a few blocks away and the most common animal in butcher shops are pigs means that the blood is most likely pig's blood." John regarded the consulting detective in surprise for a few moments before a smile spread across his features.

"Brilliant, Sherlock, bloody brilliant." Sherlock nodded as if to confirm John's assessment, a small smirk lighting his features.

Yes, this arrangement could definitely work out.


End file.
